# DuctPro — HVAC Duct Sizing Calculator

> HVAC Duct Sizing Calculator (iPhone/iPad app by High Intent Labs.)

- Source: https://appshunter.io/ios/app/ductpro/id6771761655 (this page in markdown: same URL + `.md`)
- Developer: [High Intent Labs](https://appshunter.io/developer/6771761657)
- Category: Utilities, Productivity
- Price: Free
- Age rating: 4+
- Requires: iOS 17.0 · 3 MB
- Languages: American English
- Released: 2026-05-26
- Data updated: 2026-06-09
- User reviews in markdown: https://appshunter.io/ios/app/ductpro/id6771761655/reviews.md

## What is DuctPro?

DuctPro is the professional HVAC duct sizing calculator built for field technicians and MEP engineers. Get engineering-grade results in seconds — offline, no subscription.

RESULTS IN 3 TAPS
Enter airflow, select duct type, get the size. Round, rectangular, flat oval, and flexible ducts. Size by friction rate or air velocity. A color-coded performance badge tells you instantly if your duct is optimal, too fast, too slow, or at risk.

ENGINEERING-GRADE ENGINE
Calculations use the Darcy-Weisbach friction equation with Colebrook-White solver — the industry-standard method for duct design. Nine material types with published roughness values: galvanized steel (spiral & rectangular), flexible duct (metallic & non-metallic), fiberglass duct board, fibrous glass liner, PVC, aluminum, and concrete.

FITTINGS & PRESSURE DROP
Calculate total system pressure drop including straight run and all fittings. Ten fitting types with industry-standard loss coefficients: 90° and 45° elbows (round and rectangular), mitered elbow, tee branch and straight-through, concentric reduction, enlargement, and butterfly damper.

PRO MODE
Unlock full 2D lookup tables for rectangular elbows and concentric reductions, plus A/B ratio selector for flat oval ducts. Bilinear interpolation for accurate results at any H/W or area-ratio geometry.

ORGANIZE YOUR WORK
Save calculations with a custom name and notes. Group them into color-coded projects. Export individual calculations as text or PDF, and full projects as CSV. Search your entire history in one tap.

IMPERIAL & METRIC
Switch between I-P and SI units at any time. All inputs and outputs update instantly across every screen.
I-P: CFM · in · ft/min · inWC/100ft
SI: L/s · mm · m/s · Pa/m

6 LANGUAGES
English · Français · Español · Português · Deutsch · Italiano

— 100% offline. No account. No subscription. —


## Version history (last 2 releases)

### 1.1 — 2026-06-01

- We add iPad support of the app. 
- You can now rate the app from the settings.

### 1.0 — 2026-05-26

No release notes.

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*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-06-09.*